LED lenses make eyes light up

21 Jan 2008

Contact lenses with imprinted LEDs could benefit drivers, pilots, or patients with impaired vision.

LED lens

The prototype lenses developed at the University of Washington include red light-emitting diodes and an electronic circuit, although trials to date have focused on wearability studies and have not included turning on the LEDs. The lenses were tested on rabbits for up to 20 minutes and the animals were said to show no adverse effects.

"Looking through a completed lens, you would see what the display is generating superimposed on the world outside," said Babak Parviz of the University of Washington. "This is a very small step toward that goal, but I think it's extremely promising."

Researchers built the circuits from layers of metal a few nanometers thick and LEDs one third of a millimeter across using microscopic-scale manufacturing techniques. The shape of each tiny component dictated which piece it could attach to, and a self-assembly process driven by capillary action pulled the pieces into position on a sheet of flexible plastic.

The trial lenses did not provide vision correction, but the technique could be used on a corrective lens and does not obstruct the wearer's vision. "There is a large area outside of the transparent part of the eye that we can use for placing instrumentation," said Parviz.

eye test

A full-fledged display will not be available for a while, but a version with a basic display of just a few pixels could be operational "fairly quickly", according to Parviz. Other improvements in the future could include adding wireless communication to and from the lens. The researchers hope to power the whole system using a combination of radio frequency power and solar cells placed on the lens.

Drivers or pilots wearing functioning lenses could see their vehicle's speed projected ahead of them, while video-game players could feel themselves immersed in a virtual world without restrictions on their range of motion. Web surfers could see the internet on a virtual screen visible only to them. "People may find all sorts of applications which we have not thought about," said Parviz. "Our goal is to demonstrate the basic technology, and make sure that it works and that it's safe."